Pore size distribution of an alkali activated cementitious (AACM) mortar

This paper reports an investigation on the size and distribution of capillary and gel pores in an alkali activated cementitious (AACM) mortar and comparative OPC mortar. These pore properties were determined from the cumulative and differential pore volume curves obtained by mercury intrusion porosimetry (MIP). The classification and distribution of these pores provides a useful insight to the properties of hardened concrete such as the durability, fire resistance and mechanical properties. The results show that AACM mortar mixes possess a bimodial pore size distribution while OPC concrete has unimodial pore sizes distribution. The intrudable porosity is lesser in AACM mortar than OPC mortar. The volume of the capillary pores was higher in AACM mortar compared with OPC mortar. However, the volume of the gel pores was much lower in AACM mortar than OPC mortar. The distribution of bimodal pores in AACM mortar is greatly influenced by the effects of curing type and the activator dilution. The distribution of unimodal pores in OPC mortar is similarly influenced by the curing type

Characterization and pore structure of rice husk ash cementitious material

An Investigation on the mineralogical and chemical characterization, pore structure, chemical shrinkage and pozzolanic activity of commercially produced rice husk ashes (RHA 1 and 2) and a control silica fume (SF) are presented in this paper. RHA possesses high silica content like silica fume which is used as supplementary cementitious materials (SCM) in the production of concrete. There is a need for an alternative to silica fume in the production of concrete because of its high demand and relatively high cost. The mineralogical composition of RHA 1 and 2 show high silica content of 77% and 84% respectively which is close to the silica content (˃80%) of class 2 silica fume. The oxides of Ca are 3.53% and 7.68% while Al is 1.19% and 1.29% for RHA 1 and 2 respectively which suggest that RHA is a low Ca+2 content binder. The results of chemical shrinkage of RHA 1, 2 and SF are 0.42 mL/g, 0.52 mL/g and 0.11 mL/g after 500 hrs of hydration. This indicates that RHA 2 has the highest reactivity (hydration) with water due to its highest Ca+2 content

An ethical approach to the xenophobia against foreigners in South Africa

Solomon (2013) argues that Xenophobia, simply put, is the fear or hatred of foreigners or strangers; it is embodied in discriminatory attitudes and behaviour, and often culminates in violence, abuses of various types, and manifestations of hatred. Theoretically, he argues that the best and only solution is to remove enemy images; therefore, the goal of removal of the enemy images ought to be pursued with much conscientiousness. To this extent, this paper systematically attempts to deploy an ethical approach to explore the problem of xenophobia which has pervaded the attitudes of South Africans in recent times (Mnyaka, 2003). The work will attempt to uncover what has contributed to the enemy images of foreigners, and how such images can be removed from or, failing that, substantially ameliorated in the national consciousness of South Africans so as to change for the better, the current antipodal relations between indigenous South Africans and foreigners. Specifically, the work takes as its point of departure the ethical framework of Botho/Ubuntu to dialogue with the problem of the study, emphasizing the role of political leadership to this effect (Dalamo, 2013:7)

Revenue Generated Internally in Oyo State, Nigeria: A Catalyst for Local Service Delivery

This research was designed to investigate nexus between internally produced revenue and local level service provision in Oyo Sate. This was done by investigating the results of locally raised funds to service provision at the grassroot and analyses the degree to which service provided at the local authority have improved the lives of the people within the study region. The methodology employed the use of primary data gathered through the distribution of surveys to the certain categories of people in both Ibadan Northeast local government and Ibarapa East local government. With the use of the ordinary least square approach simple utilizing a regression analysis to test the effects as well as a significance level test at 5%. It was discovered that internally generated revenue has (R = 0.850a, p < 0.05) significant impact on service delivery at the grassroots level. It therefore concluded that funds generated inwardly by the local authorities are more proper and efficient to make provision for services delivered to the local populace

Trafficking in Nigerian Cultural Antiquities: A Criminological Perspective

Antiquity trafficking has over time remained at the margin of criminological discourse in Nigeria. This silence from the criminological lens is, however, not an indication that the country is immune from the criminal activities of antiquity traffickers, but rather, it is a reflection of the common belief that this form of criminality is less rampant in Nigeria. This paper therefore examines the nature, causes, consequences and the control of the problem of illicit trafficking in the Nigerian cultural antiquities. Author adopts Cohen and Felson’s (1979) routine activity theory of crime to explain indices that formed the interplay of antiquity trafficking in the country. The author contends that factors promoting this form of crime are multidimensional, and this criminal practice has long-term negative effect on the Nigerian cultural history. A comprehensive plan of action is advocated as a practical step to effectively tackle this problem

Durability Properties of an Alkali Activated Cementitious Material

The utilization of Portland cement as a construction material is unsustainable due to the huge amount of CO2 emissions coupled with the high energy demand during its production. New innovations in low impact construction materials require a reduction in the use of Portland cement with alternative binders, preferably utilising industrial waste materials and aggregates made from recycled waste. Alkali activated cementitious materials (AACMs) shows potential benefits when used in place of Portland cement in the construction industry. However, market forces mitigating against the acceptance of AACMs are fomidable. This is partly because of the limited knowledge of the in-service life of AACM concrete, which is linked to the inadequate durability investigations available in literature. This research project investigates the durability properties of AACM concrete by exposing it to deleterious substances that cause deterioration and damage to reinforced concrete structures. The durability properties of AACM concrete were investigated under long term exposure to chloride and CO2 environments which are the two main corrosion initiators in reinforced concrete structures. Four series of AACM concrete mixes were studied with a parallel OPC concrete mix used for the comparative analysis. Mix parameters investigated in the research included factors such as activator dilution and liquid/binder ratios which are given in relevant chapters. Chapter 1 provides an Introduction to the thesis. Chapter 2 gives an overall Literaure Review and also provides information on the materials used in the research. A chapter specific literature review is given at the start of each chapter. The third chapter presents the investigation of the microsrtucture of AACM and OPC mortar mixes which shows that AACM mortar has less porosity than OPC mortar. However, a greater capillary pore volume was observed in AACM mortar than OPC mortar but the reverse was the case for gel pore volume. The fourth and fifth chapters investigate the physically bound, chemically bound and free chloride concentrations in both AACM and OPC concrete. The results show a lower degree of physically and chemically bound chlorides but a higher degree of free chloride in AACM concrete compared with OPC concrete. The free chloride/hydroxyl ion ratio which is an index for corrosion initiation in concrete is lower in AACM concrete than OPC concrete due to the higher pH of the former. The sixth chapter investigates the carbonation in AACM and control OPC concrete. The depth of carbonation is higher in AACM concrete than OPC concrete but the phenolpthlain test method has limitations for use in AACMs. Investigations on the pH of carbonation specimens gave a greater insight to carbonation in AACMs. The influence of mix design parameters of AACMs are reported in each chapter 3, 4, 5 and 6. The seventh chapter reports the monitoring of the corrosion activity of steel reinforcing bars embedded in AACM and OPC concrete until 860 days of cyclic exposure in a 5% NaCl solution and air. The corrosion potentials and current densities were higher in AACM concrete than OPC concrete under wet cycles, which is likely due to the insufficient oxygen concentration at the steel interface. The visual inspection of the reinforcing steel bars in AACM and OPC concrete to detect when corrosion begins will confirm the insufficient oxygen concentration at the steel interface. Generally, AACM concrete shows better durability properties than OPC concrete except the carbonation aspect which requires further investigation. The likehood that the phenolpthalein indicator method which is a standard testing method for carbonation of OPC concrete might not be suitable for AACM concrete

The Imperative of Information Literacy in the Digital Age: Challenges and Solutions

In the rapidly evolving digital landscape, the ability to critically evaluate, manage, and utiliseinformation effectively including an understanding of the ethical issues related to informationhas become an essential skill. This paper,through the review of literature, discusses the growingimportance of information literacy in the digital age, emphasising its role in enablingindividuals to navigate the overwhelming abundance of online content effectively. The paperdiscusses several important issues, such as the critical role of information in fosteringinteraction due to the increased information flows between parties, both individuals andorganisations, the abundant information choices, the direct correlation between a country\u27sinformation wealth and its material prosperity and the long term effect of information on societyand the economy.It discusses the growth of the digital platforms,its role in facilitating so manyof our everyday tasks,the inability to guarantee the reliability, accuracy, or quality ofinformation found online, its pervasive role in the transmission of false information and theinadequacy of AI systems.It discusses the concept of information literacy, its importance inpreparing people for lifelong learning and a democratic society; its role in promoting economicgrowth, education, health, and human services, among other facets of modern societies, anditscontribution to the competitive advantage of individuals, businesses, regions and countries. Thepaper also discusses the role of education in inculcating information literacy, the need for itsinclusion in the curriculum, and for collaboration among the stakeholders. It discusses thechallenges and the strategies for promoting information literacy,the need for institutions,government agencies and organisations to create policies that incorporate and encourageinformation literacy, offering support through provision of facilities and supportiveenvironment, and stressing the value of information literacy while specifying methods to beemployed in teaching and engaging students. By addressing these issues, the author hopes topromote digital fairness, strengthen the information society, and enable people and communitiesto make wise decisions. In order to guarantee ethical and sustainable use of the digital world,this paper emphasises how vital it is to incorporate information literacy into the educationalsystems

Influence of curing on pore properties and strength of alkali activated mortars

The paper investigates the effect of wet/dry, wet and dry curing on the pore properties and strength of an alkali activated cementitious (AACM) mortar. The pore characteristics were determined from the cumulative and differential pore volume curves obtained by mercury intrusion porosimetry. AACM mortars possess a bimodal pore size distribution while the control PC mortar is unimodal. AACM mortars have a lower porosity, higher capillary pore volume, lower gel pore volume and lower critical and threshold pore diameters than the PC mortar which indicate greater durability potential of AACMs. Wet/dry curing is optimum for AACM mortars while wet curing is optimum for the PC mortar. Shrinkage and retarding admixtures improve the strength and pore structure of the AACMs

The Rule of Law and TRC Process in South Africa

This paper is drawn from an unpublished doctoral thesis ‘Speaking Truth to Power and the Work of Albie Sachs’.  It endeavours to undertake a limited exploration of some of the implications of Albie Sachs’ role for embedding the legitimacy of the rule of law in South Africa.  It also seeks to analyse some its interactions with the Truth and Reconciliation process and explore the contestation of the concept of the ‘rule of law’.   More specifically, it attempts the consideration of what was a distorted but legalised distribution of power brought about by a warped social system, backed by strong-willed security forces that South Africa presented and also goes on to consider the consequences of the Truth and Reconciliation Commission for South Africa’s political system. [1] It raises the question of whether this impacts on the development of a human rights culture in South Africa. Historically South Africa in an effort to put its past firmly behind, ‘power’ within it constructed the Truth and Reconciliation Commission process using it as a model for reconciliation and nation building.[2] The origins of this could be situated within the setting up of the ANC’s own internal commissions of enquiry, the Stuart, Skweyiya and Motsuenyane Commissions to address its own internal violations of human rights.  These had formed the basis on which the Truth and Reconciliation Commission (TRC) was set up.  The reports of the Commissions confirmed that gross human rights violations had taken place within the ANC camps.   It is these reports that eventually prompted the promise to set up the TRC, which came into being after the transition to multi-party democracy.[3] Following a period of truth recovery, the TRC, in October 1998 presented its final report to President Mandela.[4] In the report it buttresses the argument about its attempt to put the past behind. The President in response made some attempt to locate within the establishment of the TRC, the creation of a process, which allowed people to penetrate the thoughts and objectives of those who inhabited the power structures.  It also drew from various views and positions on why its establishment was considered necessary.[5] This position can be explored with the knowledge of the argument advanced by some that South Africa was faced with the use of a legal framework for what was essentially a spiritual/psychological process.[6] The process, however, could not be successful if it was considered illegitimate by the people.  I suggest that legitimacy is about the people, including their interests, consent, value system and will.    It could therefore be argued that every law including the constitution must pass the test of legitimacy to have force.  We may venture further to suggest that the people in a republic are the superior force of the land.  That any law, including the constitution, which fails the test of legitimacy, will lose its power and if it remains unrepealed the people may under the doctrine of necessitas no habet legem ignore it by civil disobedience or revolution. It is in light of the above we explore the preamble of the Constitution of the Republic of South Africa 1996 as adopted on 8 May 1996 and amended on 11 October 1996 by the Constitutional Assembly.  The paper seeks to argue that this forms a starting point in the legitimacy process, particularly the section that recognises and acknowledges the past, where the draftsmen express the desire to reconcile the past with the present and bring together these together as a basis for healing a divided and traumatised society and, also as a means of improving the quality of life of all citizens and in the process freeing the potential of each individual.  That position also seems to be reinforced by the Act No.34 of 1995: Promotion of National Unity and Reconciliation Act 1995. The act lays down the legal framework for the functioning of the Commission, providing for the investigation and establishment of as complete a picture as possible of the nature, causes and extent of gross violations of human rights committed during the period from 1 March 1960 to the cut-off date contemplated in the Constitution.  The implication of these two statutes and indeed others grounding the work of the Commission is the creation of a situation where the South African society simply says to the perpetrators and collaborators of apartheid confess all, your sins are forgiven and there is reconciliation.  If this is the case then we must be asked by what means exactly did the Commission hope to verify without powers of the law courts that all truth had indeed been confessed?  There is doubt whether this can be answered, since it is argued that truth claims in themselves do not flourish in a climate of genuine knowledge, but in a climate of power.[7] John Eldridge argues that there is also the problematic of dealing in a world of unassailable facts, not with provisional accounts.[8] In order to explore in further detail some groundings of the Truth Reconciliation Commission reference is made to some of the views of its members.   Pumla Gbodo-Madikizela, who was a member of the TRC’s Human Rights Violation Committee, asked: ‘Why is it necessary to lift the veil from our past?  Why not simply erase the page and start all over again?’ Her attempt to answer the question refers back to the enabling act,[9] which enjoined the Truth and Reconciliation Commission to ensure the restoration of dignity to people who have suffered pain and loss through atrocities of the past.  She goes on to add that: ‘The Truth and Reconciliation Commission starts with the assumption that the truth will heal and rebuild a shattered past’.[10] Some commentators in comparing this model with those of other nations have raised the question whether the South African experiment seems to have been built upon the condition that power engages truth with a view to engendering reconciliation.[11] While others have chosen to describe it as a mechanism perceived by the South African elite as the most effective way to mend their wounds of the past and a means of moving forward in an era of majority rule.[12] This brings us to the question whether the Truth Commission can be said to be based on a number of presuppositions about political psychology among which is that knowledge promotes forgiveness and that reconciliation flows from truth, and that these were used as a mechanism to exercise control over the agenda in ways which kept potential issues out of the political/decision making process. That is, public exposure of the power behind truth was avoided. However, this does not fully address issues of legitimacy provoked with the creation of the Truth Commission.  Some claimed that international law and convention forbade granting amnesty for crimes against humanity as well as torture and similar offences.  Their slogan was: ‘No amnesty, no amnesia, justice’.[13] This issue of the legitimacy of the ‘rule of law’ also arose from a direct challenge to the whole truth and reconciliation process in the case of Azanian Peoples Organisation (AZAPO) and others v President of the republic of South Africa, which was brought before the South African Constitutional Court. It is suggested that these related to the problems relating to the amnesty provisions as laid down in the Act setting up the Commission.  There are those in South Africa, some organisations and individual families, who had suffered very grievously from human rights violations who believed that there ought to have been no amnesty provisions whatsoever.  They wanted nothing more and nothing less than trials, prosecutions and punishment.  More especially they were concerned that in term of the Act those who applied for amnesty and were successful will never again be liable, either criminally or civilly.  Some were even prepared to accept that even if amnesty had to be granted as the price for peace and stability in South Africa there still ought to be an opportunity to bring civil action against the organisation, the state or the individual.[14] In that case the constitutionality of the section was upheld.  The Court conceded that the section limited the applicants' right to "have justiciable disputes settled by a court of law, or . . . other independent or impartial forum".  However, it considered that the epilogue to the interim Constitution (the "National Unity and Reconciliation" section) sanctioned the limitation on the right of access to courts.[15] The decision of the Court confirmed the legitimacy of the process but in doing so put into effect the denial of the normal due process of access to the law courts to the victims of human rights abuses. The dilemma faced was simply that if people are encouraged to apply for amnesty but remained liable in a criminal court or in a civil court, what is the incentive for their coming forward?  The application did not succeed in court. Dr. Borraine, the Vice Chairman of the South African Truth and Reconciliation Commission argues that within the restraints of a negotiated settlement major compromises had to be made and he believed that South Africa's Truth and Reconciliation Commission has achieved the best possible outcome.[16] South Africa has decided to say no to amnesia and yes to remembrance; to say no to full-scale prosecutions and yes to forgiveness.  Those who have committed violations of human rights will, if they applied for amnesty, in most instances go free.  In South Africa's circumstances where there was no victor and vanquished, it really has no other alternative but to follow this route.  It should be borne in mind, however, that the administration of the justice process continues.  Already there have been prosecutions and there will obviously be more.  And if perpetrators declined to apply for amnesty they face the possibility of prosecution at some future date.  But it did raise the question of how many such trials can South Africa afford, not merely in financial terms but in the damage that this can do when skeletons constantly fall out of the cupboard, bringing with them further divisions and recriminations.  Indeed what occurred above appears to confirm that power in South Africa deliberately decided to make some exception to the application of the rule of law in other to facilitate a reconciliation process.  How does that seeming expediency affect the legitimacy of the rule of law? [1] Corder, Hugh (2010)., Challenges to the Rule of law in South Africa download  on 11th October 2013 from http://wwww.freedomunderlaw.org/wp-content/files/Challenges_to_the_Rule_of_Law_by_Prof_ Hugh_Corder.pdfHugh [2] Ojedokun, Olu (2003)., Interview with Jewish members of the audience at the Jewish Book Festival 2003: At the Jewish Book festival in March 2003 I was opportuned and honoured to be part of a group discussion with some other elderly Jews.  My contribution/question to them was simple.  If they had been a Truth and Commission style hearing rather than a Nuremberg hearing would they have been healing, would it have made any difference?  They thought that it might because for a lot of them after the trials of a few figure heads the atrocities were swept under the carpet and it is now this next generation that has to deal with it. [3] Truth and Reconciliation Commission of South Africa, Volume One (1998); Oxford: Macmillan p. 52 [4] Mandela, Nelson (2004); In His Own Words From Freedom to the Future  Tributes and Speeches Asmal, Kader et al pp 133 -136. [5] Boraine, Alex (1996); Op Cit [6] Storey, Peter (1994); Paper presented at The Centre for the Study of Violence and Reconciliation conference on 18 August 1994: Making Ends Meet: Reconciliation and Reconstruction in South Africa, World Trade Centre, Johannesburg [7] See Havel, Vaclav (1987); Living in Truth. London: Faber. p.156 -202 in Vardy, Peter (1999) (ed)., What is Truth?  Sydney: University of New South Wales Press [8] Eldridge, John (1993); Getting The Message News, Truth and Power London and New York: Routledge p 5 [9] Promotion of Nationality Unity and Reconciliation Act 1995 No 34 of 1995 [10] Gobodo-Madikizela, Pulma (1996); Re-enactment of Old identities &amp; implications for Reconciliation read at the 40th Annual Convention of the institute of Personnel Management, 21-23 October 1996, Sun City [11] Strategic Choices in the Design of Truth Commissions (2003s. 2 May 2002 avaliable at [http://www.truthcommission.org/commission.php?cid=3&amp;case_x=0&amp;lang=en [12] Gunnar, Theissen (1997)., Between Acknowledgement and Ignorance: How white South Africans have dealt with the apartheid past. Johannesburg: Centre for the Study of Violence and Reconciliation. para 1.1 - The Impact of Political Culture on the Consolidation of Democracy. [13] Verwoerd, Wilhelm (1997)., Justice after Apartheid? Reflections on the South African Truth and Reconciliation Commission available at [http://www.truth.org.za/reading/justice.htm] [14] Azanian Peoples Organisation (AZAPO) and others v. President of the Republic of South Africa, Constitutional Court, http://www.icrc.org/ihl-nat.nsf/0/067632d55386102cc1256b09003f0eac?OpenDocument .  The relevant summary of the case is as follows: “The applicants applied to the Constitutional Court for an order declaring section 20(7) of the Promotion of National Unity and Reconciliation Act unconstitutional. Section 20(7) permits the committee on amnesty established by the Act to grant amnesty in respect to any act, omission or offence provided that the applicant concerned has made a full disclosure of all relevant facts, and provided further that the relevant act, omission or offence was associated with a political objective and committed prior to 6 December 1993. As a result of the granting of amnesty, the perpetrator is relieved from criminal or civil liability. The State or any other body, organisation or person that would ordinarily have been vicariously liable is also relieved from liability.  The constitutionality of the section was upheld. The Court also considered the argument that the State was obliged by international law to prosecute those responsible for gross human rights violations and that the provisions of section 20(7) authorising amnesty for perpetrators constituted a breach of the Geneva Conventions of 1949…………… The Court held that it was doubtful whether the Geneva Conventions and their Additional Protocols applied at all to the conflict. In any case, Additional Protocol I was not binding on South Africa and Additional Protocol II actually encouraged the authorities in power to grant amnesties after the end of hostilities. The Court held further that international law distinguished between international and non-international armed conflicts. For the latter category there was no obligation to prosecute those who might have performed acts of violence or other acts, which would ordinarily be characterised as serious violations of human rights. [15] Op  Cit. [16] Strategic Choices in the Design of Truth Commissions. Op Cit